Background: This study examines the downstaging of breast cancer axillary lymph node (ALN) metastasis by neoadjuvant chemotherapy (NCT) and the potential facilitation of axillary-conserving surgery.
Methods: Records of breast cancer patients treated with NCT, breast surgery, and pathological ALN assessment were reviewed using the institutional breast cancer database.
Results: Of 473 cases, 309 (65%) were clinically ALN-positive (cN+) and 164 (35%) were clinically ALN-negative (cN-). Pre-NCT, needle biopsy, sentinel lymph node (SLN) biopsy, or axillary dissection documented metastasis in 94% (117/124) of cN+ and 27% (13/49) of cN- patients tested. Pathological complete response of ALNs to NCT was documented in 36% (41/115) of patients. False negative SLN biopsy following NCT occurred in 4% of cases (1/28).
Conclusion: NCT downstages primary breast cancer and ALN metastasis. ALN and SLN biopsy following, rather than before, NCT facilitate both breast- and axillary-conserving surgery.